Backpiece for film cameras



Filed Jan. 3, 1930 2 Sheets-Sheet l Feb. 21, 1933. w, .WI 1,898,232

BAGKPIECE FOR FILM CAMERAS Filed Jan. 5, 1950 2 Sheets-Sheet 2 Patented Feb. 21, 1933 UNITED STATES" WILHELM WIDMANN, OF FREUDENSTADT, GERMANY BACKPIECE FOR FILM CAMERAS Application filed January 3, 1980, Serial No. 418,216, and in Germany J'anua ry 2, 1929.

.' My invention relates to back pieces for film cameras. It is an object of my invention to provide a back piece which permits the picture to be inspected on a ground-glass screen before it is exposed, and to remove apy desired film independently of the sup- P Y- To this end I provide a supply of film, usually a spool, at one side of the backpiece in o a suitable film holding compartment from which supply a. film is fed across the area of exposure. Below the path along which the film moves while being fed I provide a dark slide the lid of which when closed supports the film. At a point intermediate the film holding compartment and the area of exposure I provide a cutter for detaching the exposed film from the supply.

When thelid of the dark slide is withdrawn the film which has been separated drops into. the dark slide whereupon the lid is closed and any number of fresh films may be fed, exposed, separated and stored in the dark slide from which they may be removed for exposurel It is another object of my invention to facilitate the penetration of the film into the dark'slide. To this end I wind the film on the bobbin with the sensitive layer on the out- 0 side. The film normally arches so that the layer is on the convex side so that when released by the lid of the dark slide it is jerked intothe dark slide by its own resiliency.

The expedient of winding the film on the spool in the manner aforesaid is not the only I solution of the problem of imparting to the film an arching tendency as this tendency may also be imparted to the film during its manufacture.

It is another object of my invention to provide means for exposing only part of the film, for instance half the picture size of the camera. To this end I perforate the film at the edges in accordance with the part sizes to be exposed and provide means accessible from the outside for moving the film across the dark slide into the desired position. This is efiected by hooks engaging in the perforations which are so connected with the means as to risefrom the holes when themeans are returned to the initial position, and engage the next set of holes for feeding the following part size of film.

t is another object of my invention to so design the means for feeding the film through the medium of hooks as described that when extracted from the back piece the means serve for inspecting the picture to be exposed.

As compared with the usual film cameras having a back piece with a supply and a winding spool, my novel back plece has the advantages of permitting inspection of the, picture on a screen and of eliminating the necessity of exposing the complete supply for developing a given icture.

In the drawings a%xed to this specification and forming part thereof two types of back pieces are illustrated diagrammatically by way of example.

In the drawings Fig. 1 is a vertical longitudinal section of a back piece having rotary parts'for feeding the film,

Fig. 2 is a section on the line 2-2 in Fig. 1,

Fig. 3 is a sectional plan view of a back piece having hooks for feeding the film and exposing part sizes as described, and

Fig. 4 is a section on the line 4-45in Fig. 1. Referring now to the drawings and first to Figs. 1 and 2, 1 is a back piece, 1 is the bottom plate of the camera which is hingedjto the back iece at 1", the objective and the bellows o the camera (not shown) being housed and folded in the cavity of the back piece in the usual manner when the bottom plate 1 is in the closed position as illustrated, 2 is a film holding compartment at one side of the back piece, with a supply of film 4 on a suitable spool 5, 6 is a dark slide which is inserted at the rear of the back piece 1 in place of the usual screen, not shown, 7 7 are two bars extending along the edges of the back piece for holding the dark slide 6, the folded-over sides of the dark slide engaging in corresponding grooves of the bars, as best seen in Fig. 2, and 8'is the lid of the dark slide. 9 is a transverse bar at the wall of the back piece which adjoins the film compartment 2, and 10 is a kink in the dark slide and His aguide or lip inthe wall of the film holding compartment 2 throu h which the film 4 enters the back iece 1. l'he entering film slides on the top the bar 9 which is at the same level as the lid 8 beyond the kink 10,

and now moves on on the lid. 15 15 are resser bars with upturned ends 16 which he d the film engaged with the lid under the pressure of springs 17, 17 as best seen in Fig. 2.

' i 18 is a slotted tubular guide extending in I parallel relation with to the bar 9, 19 is a rod fitted to slide in the tube 18, and 20 is a knife which is secured to the rod 19 by means projectin thro h the slot in the tube "18. 21 is a handle on s end of the rod 19 which projects from the side of the back piece,

as shown m Fig. 2. The knife 20 and the edge of the bar 9 make ulp the cutter, the knife 20 extendin to below t e upper face of the bar. The e e of the knife 20 is referably inclined as i1 ustrated in Fig. 2 w 'eh shows the knife in an intermediate position. It will appear that the knife enters the cavit below t e film 4 which is formed by the kin 10 so that the film at this int unsupported and readily severe In operation, after the picture has been exposed the handle 21 is pulled out to move the knife 20 along the bar 9 and to sever the exposed end of the film. The film is held on the lid of the dark slide 6 by the presser bars 15 and ri 17 and when the lid 8 is extractedjzhe iifiii penetrates into the dark slide with its ends advancing, and assumes in the dark slide the arched position illustrated at 22 in Fig. 1. The lid 8 is now reinserted, forcing down the film 22, and forcing up the premer bars at their upturned ends 16.- The so back piece now ready for the reception of the ,next film which is fed forward .as described.

Referring now to Figs. 3 and 4, the back piece with the film holding com artment, the dark slide and the cutter have n indicated by the same reference numerals as in 1 and 2.

. fithepresentinstancathefilm iisperfo rated at its ed the perforations 23 being 00 pitched apart or a distance corresponding to the 'size to be e in the present instance, to half the length of the full size. The b holes are engaged by 'ooks 24 at lugs 29 pro- Jecting' from the sides of an open rectangular frame 25 which is guided in sleeves 26 in feeding a 1,ees,asa

with an arch 28. When the frame 25- has been moved to its inner final position'to engage the holes 23, at the end of a film-the 'ar 9 being recessed at 27' for the reception of the hook 24 a'nd the frame is now pulled out, the lugs 29 strike the arches 28 when the their upturned.

film has arrived in the desired position and the resistance indicates to the operator that he must not pull out the frame 25 any more.

When the film has been exposed it is severed by the cutter as described, and dropped into the dark slide 6.

The hooks 24 may be resilient or combined with some resilient means so that they will engage the perforations 23 under the action of such means. If desired, the lid 8 of the dark slide may be grooved at 30 for the reception of the lower end of the hooks. As mentioned the frame 25, when extracted, may serve for surveying the picture to be taken. v

I wish it to be understood that I do not desire to be limited to the exactdctails of construction shown and described for obvious modifications will occur to a person skilled in the art.

'* In the claims afiixedto this specification no selection of any particular modification of the invention is intended to the exclusion of other modifications thereof and the ri ht to subsequently make claim to any modi cation not covered by these claims is expressly reserved.

I claim Y i 1. A back piece for film cameras comprising film supplty;l means at one side, means for feeding a m from said sup ly means across the area of exposure, a dar slide inserted in said back piece below the path along which the film moves while being fed, a li on said dark slide adapted to support the film, and cutting means at a point intermediate said film supply means and the area bf osure.

2. back piece'for film cameras comprising film supghylmzans at one side, means for ends engaging below said bar, a lidon said. dark slide adapted to support the film, and

cutting means adapted to move along said ar. y

3. A back iece for film cameras comprising film supp y means at one side, means for feeding afi m from said supply means across rom said supply means across the area of exposure, a 'bar in said the area of exposure, a dark slide inserted in said back piece below the path along which the film moves while being fed, cutting means at a point intermediate said film sup- 5 ply means and the area of exposure and a 'd on said dark slide which is kinked for said cutting means.-

4. A back piece for film cameras compris-* ing film supply means at one side, means for feeding a film from said supply means across the area of exposure, a dark slide inserted in said back piece below the path along which the film'moves while being fed, a lid on said dark slide adapted to support the film, resilient means adapted to hold the film down on saidlid and to be displaced by saidlid, and cutting means at a pomt intermediate said film supply means and the area of ex osure.

5. back piece for film cameras comprising film supply means at one side, a dark slide inserte in said back piece below the path along which the film moves while being fed, a lid on said dark slide adapted to support the film, means adapted to be operated from the outside of said back piece and including hooks for engaging perforations in the film, and cutting means at a point intermediate said film supply means and the area of ex osure.

.6. A bac piece for film cameras comprising film sup 1 means at one side, a dark slide inserte 1n said back piece below the path along which the film moves while be- 35 mg fed, a lid on said dark slide adapted to sup ort the film, means adapted to be operate from the outside of said back piece ahd including resilient hooks for engaging perforations in the film, and cutting means at a point intermediate said film supply means and the area of exposure.

Intestimony whereof I afiix m si ature.

' WILHELM W'I NH. 

